1. Technical Field
The present invention relates to a liquid-jet apparatus such as an ink-jet recording apparatus, and more particularly relates to a liquid-jet apparatus which ejects a liquid stored in a liquid storage member from nozzle orifices in a liquid-jet head by introducing the liquid into the liquid-jet head through liquid introducing needles.
2. Related Art
There is a liquid-jet apparatus which includes a liquid-jet head capable of ejecting a liquid, and which ejects various kinds of liquid from the liquid-jet head. Representative examples of such a liquid-jet apparatus include, for example, an image recording apparatus such as an ink-jet printer which performs recording by ejecting ink droplets and having the droplets land on recording paper or the like as an ejection target (recording medium). Moreover, in recent years, the liquid-jet apparatus has been applied not only for the image recording apparatus but also for various types of manufacturing equipment. For example, in display manufacturing equipment for a liquid crystal display, a plasma display, an organic EL (Electro Luminescence) display, a FED (Field Emission Display) and the like, the liquid-jet apparatus is used for ejecting various liquid materials such as color materials and electrodes onto a pixel forming region, an electrode forming region and the like.
As the liquid-jet apparatus of this type, there have been developed a wide variety of apparatuses using a cartridge-type liquid storage member that is easily distributed and handled. For example, regarding the ink-jet printer (hereinafter, simply referred to as a printer), those using ink cartridges filled with liquid ink have been widely used. In this configuration, the ink cartridge is loaded on a cartridge loading section and ink introducing needles (liquid introducing columnar bodies) are inserted into the ink cartridge. Thus, the ink in the ink cartridge is introduced into a recording head that is a kind of liquid-jet head through ink introducing ports (liquid introducing ports) which are drilled in tips (tapered portions) of the ink introducing needles. Moreover, generally, in such an ink cartridge, for preventing leakage and evaporation of the ink to the outside, opening portions of needle insertion slots (ink outlets) provided in a bottom portion thereof are sealed with a thin breakable resin film (sealing film) made of PP (polypropylene) or the like. Moreover, when the ink cartridge is loaded into the printer, the ink introducing needles break the sealing film to be inserted into the needle insertion slots.
In the configuration using the ink cartridge as described above, an ideal state is that ink passages (liquid passages) from the ink introducing needles to nozzle orifices in the recording head are filled with the ink. However, bubbles may enter the ink passages during replacement of the ink cartridge or the like. Moreover, it is difficult to completely prevent the bubbles from entering thereinto. This is because of the following reason. Specifically, in the case of loading an unused ink cartridge, ink introducing needles are pushed into needle insertion slots in the ink cartridge. Thus, a sealing film that seals the needle insertion slots is broken by tips of the ink introducing needles. In this breaking of the sealing film, the film is flexed and temporarily adheres to the tips of the ink introducing needles. Accordingly, air compressed between the sealing film and the ink introducing needles in this adhesion state enters the ink introducing needles from ink introducing ports and becomes bubbles. Thereafter, the bubbles that have entered ink passages gradually grow in size and some of the overgrown bubbles are moved toward a pressure chamber by a flow of the ink. As a result, there may arise problems such as pressure loss due to absorption of pressure fluctuations in an ejection operation by the bubbles and insufficient supply of ink due to blocking of the passages by the bubbles.
For the purpose of preventing such problems caused by the bubbles, the following invention has been proposed. For example, according to JP-A-2006-069168, a plurality of ribs are provided in an enlarged diameter portion formed at a base of an ink introducing needle to protrude from an inner peripheral surface of the enlarged diameter portion toward its center. Moreover, bubble chambers are partitioned by both ribs adjacent to each other in the peripheral direction. By moving bubbles in an upper part (upstream side) of a filter into the bubble chambers with a flow-down force of ink passing inside the ink introducing needle, a contact area of the bubbles with the filter is increased. Thus, efficiency of discharging the bubbles is improved and the bubbles are discharged to the outside of a recording head. JP-A-2006-069168 is an example of related art.
However, the invention disclosed in JP-A-2006-069168 is for discharging the bubbles that have entered the ink introducing needle rather than preventing the bubbles from entering the ink introducing needle. Thus, in order to discharge the bubbles inside the ink introducing needle, it is necessary to frequently perform a cleaning operation for generating an ink flow having a flow rate several times higher than that in a recording operation. As a result, there is a problem of wasteful consumption of ink.